The objective of this research is to identify and study those cortical structures involved in mediating the discrimination of changes in temporal patterns of sensory stimuli. Recent data collected in our laboratory suggests that insular-temporal cortex in the cat (thought for the past 20 years to have only auditory function) is critical for the animal's ability to detect changes not only in temporal patterns of auditory stimuli, but also visual stimuli. The proposed research is designed to test the hypothesis that insular-temporal cortex is actually a multimodal area, playing a role in the discrimination of changes in temporal patterns of various classes of sensory stimuli. The basic method to be used in this proposed research is the classical ablation technique. Each animal's pre-and postoperative performance will be measured in a variety of test situations requiring perception of temporal patterns of stimuli. Cats will be tested with temporal patterns of tactile stimuli. in addition to auditory and visual stimuli. Behaviors such as detection of repetition rate, stimulus order, and simultaneousness vs. successiveness will also be investigated before and after bilateral insular-temporal lesions.